An optoelectronic device such as a photovoltaic cell, a light emitting diode (LED), or an organic light emitting diode (OLED) may include an encapsulant configured to encapsulate a light emission or light sensing region of the device.
For example, solar cell modules may be typically manufactured using a lamination process of laminating a transparent front substrate serving as a light receiving substrate, an encapsulant, a photovoltaic device, an encapsulant and a back sheet and then heat pressing the laminated body while applying a suction to the laminated body under a vacuum.
An ethylene-vinyl acetate (EVA) resin has been the most widely used as the encapsulant used for the solar cell modules in aspects of the processability, constructability, and cost.
However, the EVA resin exhibits low adhesive strength to elements included in the optoelectronic device and coming in contact with the encapsulant such as the front substrate or the back sheet. Therefore, when the modules are exposed to outdoor environments for a long period of time, they have a problem in that interlayer delamination may occur easily. Also, in a method of manufacturing a solar cell module using an encapsulant including the EVA resin, the EVA resin may be thermally cracked under hot pressing conditions, resulting in the formation of acetic acid gas, etc. Such acetic acid gas causes problems in that it worsens working environments, has a negative influence on photovoltaic devices or electrodes included in the solar cell module, and also causes degradation of the modules and a decline in power generation efficiency, and the like.
Therefore, there is a continuous demand for encapsulants for optoelectronic devices having improved long-term adhesive properties.